Primivites and Variables

Question 1

What is the purpose of variables?

Answer 1

Stores data or value to be calculated or computed.

Question 2

How do youdeclarea variable?

Answer 2

var keyword - var name;

Question 3

How do you initialize (assign a value to) a variable?

Answer 3

var varname= value

Question 4

What characters are allowed in variable names?

Answer 4

letters, numbers dollar sign or underscore

Question 5

What does it mean to say that variable names are “case sensitive”?

Answer 5

Capitalizations matter i.e camel case

Question 6

What is the purpose of a string?

Answer 6

frequently used to add new content into a page, can contain HTML markup

Question 7

What is the purpose of a number?

Answer 7

used for tasks to determine size position or setting timers for elements.

Question 8

What is the purpose of a boolean?

Answer 8

determines which part of a script should run

Question 9

What does the=operator mean in JavaScript?

Answer 9

assignment operator, updates the value given to a variable

Question 10

How do you update the value of a variable?

Answer 10

using the assignment operator

Question 11

What is the difference betweennullandundefined?

Answer 11

undefined is primitive value assigned to variables that have just been declared or to formal arguments where there are no actual arguments. Null is also primitive, every object is derived from null value and typeof returns an object, even though it generally represents a nonexistent or invalid object or address.

Question 12

Why is it a good habit to include “labels” when you log values to the browser console?

Answer 12

let’s you be explicit with values to make it easier to find problems

Question 13

Give five examples of JavaScript primitives.

Answer 13

string, number, boolean, valueof, null, undefined